Type 40BD
1/4" prepolarised, high level + high freq.
Range: 45 - 174 dB, Freq.: 10 Hz - 70 kHz
Sensitivity: 1.6 mV/Pa

Type 40BP
1/4" high level + high frequency
Range: 45 - 174 dB, Freq.: 10 Hz - 70 kHz
Sensitivity: 1.6 mV/Pa

Type 40BH
1/4" for very high level + high frequency
Range: 60 - 194 dB, Freq.: 10 Hz - 20 kHz
Sensitivity: 0.4 mV/Pa

Type 40AD
1/2" prepolarised, general purpose microphone
Range: 17 - 146 dB, Freq.: 6.3 Hz - 10 kHz
High Sensitivity: 50 mV/Pa

Type 40AG
1/2" high precision microphone for lab. work
Range: 27 - 160 dB, Freq.: 3.15 Hz - 20 kHz
Sensitivity: 12.5 mV/Pa

Type 40AP
1/2" high sensitivity, general purpose microph.
Range: 17 - 146 dB, Freq.: 3.15 Hz - 10 kHz
Sensitivity: 50 mV/Pa

Type 40AO
1/2" prepolarised, high precision lab microph.
Range: 27 - 160 dB, Freq.: 3.15 Hz - 20 kHz
Sensitivity: 12.5 mV/Pa

Type 40EN
1" pressure microphone ideal for couplers
Range: 9.6 - 146 dB, Freq.: 2.6 Hz - 8 kHz
High Sensitivity: 50 mV/Pa

Type 40DP
1/8" for very high level + high frequency
Range: 50 - 184 dB, Freq.: 6.5 Hz - 140 kHz
Sensitivity: 1 mV/Pa

Type 40AU
1/2" laboratory-standard microphone
Range: 27 - 160 dB, Freq.: 3.15 Hz - 20 kHz
Sensitivity: 12.5 mV/Pa

Type 40EU
1" laboratory-standard microphone
Range: 9.6 - 146 dB, Freq.: 2.6 Hz - 8 kHz
High Sensitivity: 50 mV/Pa

Type 40DD
1/8" prepolarised, v. high level + high freq.
Range: 50 - 184 dB, Freq.: 6.5 Hz - 140 kHz
Sensitivity: 0.7 mV/Pa

A free-field microphone is designed to measure the sound pressure in a sound field and compensate for the influence of its presence in the sound field.

A free-field microphone measures the sound pressure as it existed before the microphone was introduced into the sound field; in effect, maintaining free-field conditions.

A free-field microphone should be pointed towards the sound source, i.e. at an angle of 0 degrees incidence to the source.
 

Type 40BF
1/4" for high level and high frequency
Range: 40 - 174 dB, Freq.: 10 Hz - 100 kHz
Sensitivity: 4 mV/Pa

Type 40AM
1/2" prepolarised precision lab microph.
Range: 27 - 160 dB, Freq.: 3.15 Hz - 40 kHz
Sensitivity: 12.5 mV/Pa

Type 40AC
1/2" high precision working standard
Range: 27 - 160 dB, Freq.: 3.15 Hz - 40 kHz
Sensitivity: 12.5 mV/Pa

Type 40AE
1/2" prepolarised, general purpose
Range: 15 - 146 dB, Freq.: 3.15 Hz - 20 kHz
High Sensitivity: 50 mV/Pa

Type 40AF
1/2" high sensitivity, general purpose
Range: 15 - 146 dB, Freq.: 3.15 Hz - 20 kHz
Sensitivity: 50 mV/Pa

Type 40AN
1/2" high sensitivity, low frequency
Range: 15 - 146 dB, Freq.: 1 Hz - 20 kHz
Sensitivity: 50 mV/Pa

Type 40BE
1/4" prepolarised, high level + high freq.
Range: 40 - 168 dB, Freq.: 10 Hz - 100 kHz
Sensitivity: 4 mV/Pa

Type 40AZ
1/2" prepolarised, precision infra-sound
Range: 15 - 146 dB, Freq.: 0.5 Hz - 20 kHz
High Sensitivity: 50 mV/Pa

As with Outdoor Microphones, these G.R.A.S. Environmental Microphones are equipped with four-pronged anti-bird spikes on top of the windscreen. This prevents birds from perching on top of the windscreen when the microphone unit is placed outdoors for long-term unattended noise surveillance.

These microphones can withstand rain and operate over a wide range of temperatures over periods lasting from a few days to several weeks.

Type 41AL
for short-term outdoor measurements covering periods from a few days to several weeks
Type 41AL-S (community noise) - with externally-polarised microphone and 90 deg. incidence.
Type 41AL-1 (airport noise) - with externally-polarised microphone and 0 deg. incidence
Type 41AL-2 (community noise) - with prepolarised microphone and 90 deg. incidence
Type 41AL-6 (airport noise) - with prepolarised microphone and 0 deg. incidence
Range: 20 - 146 dB, Freq.: Type 0 for both: IEC 60651 and ANSI S1.4-1983
Sensitivity: 50 mV/Pa (nominal)

Type 41AO
Precision microphone unit (IEC 61672) for monitoring the noise of
overhead aircraft. It can withstand rain and operate over a wide range of
temperatures over periods lasting from a few days to several weeks.
Range: 14 dBA - 146 dB (41AO), 14 dBA - 135 dB(41AO-S prepolarised), Freq.: 10 Hz - 100 kHz
Sensitivity: 50 mV/Pa (nominal)

Type 41AM
0 deg. incidence, for permanent outdoor installations
Range: 20 - 136 dB, Freq.: Type 0 for both: IEC 60651 and ANSI S1.4-1983
Sensitivity: 50 mV/Pa (unified)

Type 41CN
90 deg. incidence, for permanent outdoor installations
Range: 20 - 136 dB, Freq.: Type 0 for both: IEC 60651 and ANSI S1.4-1983
Sensitivity: 50 mV/Pa (unified)

G.R.A.S. Low-noise measuring systems can measure noise levels below the threshold of human hearing, e.g. from disk drives, computer equipment in general and in quiet rooms.

A quiet location can easily be subjected to intrusive noise when many otherwise "inaudible" devices are in use.

It therefore becomes important to know in advance (through accurate measurements) the noise contribution of quiet products when many of these are to be placed in quiet working environments.
 

Type 40HF
1" for noise below human hearing threshold
Range: -2 dBA to 110 dB, Freq.: 12.5 Hz-4 kHz
Sensitivity: 1.1 mV/Pa (nominal)

Type 40HH
1/2" for noise below human hearing threshold
Range: 6.5 dBA to 113 dB, Freq.: 10 Hz-70 kHz
Sensitivity: 0.8 mV/Pa (system)

Type 40HT
1/2" as per 40HH, use in KEMAR
Range: 6.5 dBA to 113 dB, Freq: 12.5Hz-10kHz
Sensitivity: 0.8 mV/Pa (system)

Type 40HL
1/2" for measurements on very quiet products
Range: 6.5 dBA to 113 dB, Freq.: 12.5Hz-10kHz
Very High Sensitivity: 900 mV/Pa (system)

Specially designed for difficult measurement situations, for example in high temperatures (up to 800 degrees C) or airflow.

The right-angle design makes the probe microphone particularly well suited for measurements on exhaust systems and other machinery in general, as well as for scanning surfaces such as loudspeaker cones and loudspeaker cabinets.

Its very small size, low weight and all stainless-steel construction, make the probe robust, easy to handle and simple to mount.
 

Type 40SC
prepolarised microphone and preamplifier, requires a constant-current power supply
Upper Limit: >160 dB, Freq.: 2 Hz - 20 kHz
Sensitivity: 3 mV/Pa (nominal)

Type 40SA
small, compact unit for use in small enclosures, harsh environments and very close to sources.
Upper Limit: >174 dB, Freq.: 2 Hz - 20 kHz
Sensitivity: 3 mV/Pa (nominal)

A random incidence microphone is designed essentially to measure sound pressure levels in a diffuse sound field as they existed before the microphone was introduced into the diffuse sound field. At higher frequencies, the presence of the microphone in the sound field becomes more significant and will influence the measured sound pressure levels.

In general, the sound pressure around the microphone cartridge will increase because of reflections and diffraction. This pressure increase varies with different incidence directions. A random-incidence microphone is designed so that it's frequency response characteristics compensate for this pressure increase, assuming that the sound waves arrive at random from all directions.
 

Type 40AR
1/2" optimised to measure sound pressure levels in random, diffuse or reverberant fields
Range: 17 - 146 dB, Freq.: 3.15 Hz - 16 kHz
Sensitivity: 50 mV/Pa

Type 40AQ
1/2" prepolarised, measures sound pressure levels in random, diffuse or reverberant fields
Range: 17 - 146 dB, Freq.: 3.15 Hz - 16 kHz
Sensitivity: 50 mV/Pa

A window microphone is a useful tool for measuring community noise striking the facades of, say, hospitals, offices and dwellings.

It can also be used to provide a useful assessment of current or improved sound proofing in buildings continuously exposed to external noise, e.g. from road traffic.
 

Type 41AW
meets the current Swiss code of practice for measuring noise at window-pane
location main components of the Window Microphone are a preamplifier
(Type 26AC) and microphone (Type 40AF) mounted on a 160 mm aluminium disc
Range and Frequency Response as per Type 40AF

A surface microphone is for use in places where sound measurements are performed in the presence of air flow, e.g. on the external surfaces of vehicles either in motion or in wind tunnels.

It must be possible to flush mount it on planar and curved surfaces and be little affected by the curvature of the surface at the mounting point.
 

Type 40PS
low cost unit for general purpose measurements on planar and curved surfaces
Upper Limit: 136dB, Lower Limit: < 30dBA, Freq.: 100 Hz - 3 kHz
Nominal Sensitivity: 5 mV/Pa at 250 Hz

Low cost microphones for general purpose measurements in arrays and matrices. They have an integrated CCP (Constant Current Power) preamplifier and built-in TEDS (Transducer Electronics Data Sheet - as proposed by IEEE-P1451.4) enabling them to be programmed as a complete unit
 

Type 40PH
Upper Limit: 135dB, Freq.: 10 Hz - 20 kHz
Sensitivity: 50 mV/Pa

Type 40PL
Upper Limit: 150dB, Freq.: 10 Hz - 20 kHz
Sensitivity: 10 mV/Pa